1. Field
Embodiments of the present invention generally relate to the field of heat dissipation in electromechanical devices and, more particularly, to the cooling of actuator coils.
2. Background
Motor coils are used in a wide array of applications including, for example, hard disk drives and lithography tools. In general, a motor coil includes an actuator coil that contains numerous windings of a wire and a magnetic device. The magnetic device can include one or more permanent magnets. As electric current is passed through the actuator coil, an electromagnetic field is established, which interacts with a magnetic field produced from the magnetic device to cause a force to be exerted on the actuator coil. This force causes the actuator coil to move. In the alternative, the magnetic device can move, while the actuator coil remains stationary, when the electromagnetic field is established between the magnetic device and the actuator coil.
The movement of the actuator coil can be controlled by adjusting the electric current flowing through the actuator coil, where a force on the actuator coil is proportional to the electric current. To increase the force, the electric current must also be increased. However, as the current is increased, the operating temperature of the actuator coil also increases in the form of electrical energy dissipating as heat energy within the actuator coil. The resistance of the actuator coil, in turn, increases and the magnitude of the current flowing through the actuator coil is limited, thereby adversely affecting the performance of the motor coil.
One common solution for applications requiring a rapidly moving motor coil is the use of heat transfer elements. Current heat transfer elements are placed on top, bottom, and side surfaces of the actuator coil and configured to cool the outside layers of the coil. However, these heat transfer designs do not effectively transfer heat away from the inner layers of the coil, where coil temperature can be at its highest.